Am I doing Canon flats wrong?

[Fay]

I have just read that darks have to be the same ISO & length of time as L. Which is ok.
Then I read that the flats have to be the same ISO as well. I did wonder why DSS tells me that the ISO of the flats is different.
I usually do them at ISO 100 for 0.5 secs.

Am I wrong?

   

[Daniel]

No, im pretty sure it's ok, I shoot mine at ISO 100 too, the only thing the ISO will introduce is more noise, which you don't want in flats anyway.